public MyDxfArc(double in_XCenter, double in_YCenter, double in_StartDegreeAngle, double in_EndDegreeAngle, double in_Radius, string in_Layer)
{
XCenter = in_XCenter;
YCenter = in_YCenter;
StartAngleRad = MathHelperForTransformations.ConvertDegreesToRadians(in_StartDegreeAngle);
StartAngleDegree = in_StartDegreeAngle;
EndAngleDegree = in_EndDegreeAngle;
EndAngleRad = MathHelperForTransformations.ConvertDegreesToRadians(in_EndDegreeAngle);
layerIdentifier = in_Layer;
doneTransformationOfAngle = false;
if (EndAngleRad < StartAngleRad)
{
EndAngleRad += 2 * Math.PI;
doneTransformationOfAngle = true;
}
Radius = in_Radius;
}
/// <summary>
/// calculate bound box for arc
/// </summary>
/// <returns></returns>
public override MyDxfBoundingBox GetBoundingBox()
{
//convert to ccw
double alphaPrecomputedDegree = StartAngleDegree % 360;
double alphaPrecomputedRad = MathHelperForTransformations.ConvertDegreesToRadians(alphaPrecomputedDegree);
double bethaPrecomputedDegree = EndAngleDegree % 360;
double bethaPrecomputedRad = MathHelperForTransformations.ConvertDegreesToRadians(bethaPrecomputedDegree);
if (doneTransformationOfAngle)
{
bethaPrecomputedRad += Math.PI * 2;
bethaPrecomputedDegree += 360;
}
System.Diagnostics.Debug.Assert(alphaPrecomputedRad < 360);
//arc endpoints
double YZeroAlpha = YCenter + Radius * Math.Sin(alphaPrecomputedRad);
double XZeroAlpha = XCenter + Radius * Math.Cos(alphaPrecomputedRad);
double YZeroBetha = YCenter + Radius * Math.Sin(bethaPrecomputedRad);
double XZeroBetha = XCenter + Radius * Math.Cos(bethaPrecomputedRad);
//next, find all points on circle that divide it by 90 degrees (polar points, name it) between two angles defining the arc
// https://stackoverflow.com/questions/1336663/2d-bounding-box-of-a-sector
//maximum 4 points
List <double> polarPointsXCoordinates = new List <double>();
List <double> polarPointsYCoordinates = new List <double>();
double angularCounter = Math.Ceiling(alphaPrecomputedDegree / 90) * 90;
while (angularCounter < bethaPrecomputedDegree)
{
if ((angularCounter % 360 == 0) || (angularCounter == 0))
{
polarPointsXCoordinates.Add(XCenter + Radius);
polarPointsYCoordinates.Add(YCenter);
}
else if (angularCounter % 270 == 0)
{
polarPointsXCoordinates.Add(XCenter);
polarPointsYCoordinates.Add(YCenter - Radius);
}
else if (angularCounter % 180 == 0)
{
polarPointsXCoordinates.Add(XCenter - Radius);
polarPointsYCoordinates.Add(YCenter);
}
else if (angularCounter % 90 == 0)
{
polarPointsXCoordinates.Add(XCenter);
polarPointsYCoordinates.Add(YCenter + Radius);
}
angularCounter += 90;
}
MyDxfBoundingBox resultBox;
List <double> allPointsY = new List <double>();
allPointsY.AddRange(polarPointsYCoordinates);
allPointsY.Add(YZeroAlpha); allPointsY.Add(YZeroBetha);
List <double> allPointsX = new List <double>();
allPointsX.AddRange(polarPointsXCoordinates);
allPointsX.Add(XZeroAlpha); allPointsX.Add(XZeroBetha);
resultBox.YUpperRight = allPointsY.Max();
resultBox.YLowerLeft = allPointsY.Min();
resultBox.XLowerLeft = allPointsX.Min();
resultBox.XUpperRight = allPointsX.Max();
return(resultBox);
}